"Arguably the single most important factor in your quality of life is what we choose to focus on. This is true both in the short term, in that what you focus on in any given moment determines how you feel in any given moment, and it’s also true in the long term: what you focus on over an extended period of time determines what you do or don’t accomplish and create for your life. So your internal quality of life is based on what you’re focusing on in the moment, and your external quality of life in terms of your circumstances, your relationships, is based on what you focus on consistently over an extended period of time. The single most determining factor in your quality of life, both short term and long term, is what you focus on."

— Hal Elrod, Achieve Your Goals Podcast